I already do this using Notepad++, edit your files using Notepad++ and keep working on your site using WinSCP. You can even open multiple files and edit multiple files simultaneously with Notepad++ and as soon as you hit the save button in one of the open files in Notepad++ Winscp will automatically update the file on the server, you dont even have to manually upload the file. Open settings and replace internal editor with Notepad++.
The reason that I am requesting this is due to me working on large files. I have to wait for the file to download and the file sizes usually span between either a couple of Megs to Gigs. To be specific it takes a while for me to download a 4GB file and I have to do multiple edits to the same file.
So what happens when I open the file is that all WINSCP sessions are locked until that file is downloaded and some files take anywhere between 20-30 min to an hour sometimes. So this would be a nice to have to push the large files to a background process that will not interfere with one working in a session. I am not sure if moving the background process to it's own process thread would solve this?
These are files I don't usually keep open in my editor(notepad++) and I am usually openining them for the first time to research an issue.